Disclosed is a benzonitrile derivative which is useful as a production intermediate for benzylamine derivative represented by the general formula (5) below and s secondary amine derivative represented by the general formula (9) below. Also disclosed are a method for producing such a benzonitrile derivative and a use thereof as a bactericide. Specifically disclosed are a novel benzonitrile derivative represented by the general formula (1) below, a salt thereof, a production method thereof, and a use thereof as a pharmaceutical intermediate or a bactericide. [Chemical formula 1] (5) (In the formula, n represents an integer of 0-3, and R1 represents a hydrogen, a linear or branched alkyl group having 1-6 carbon atoms or the like.) [Chemical formula 2] (9) (In the formula, n and R1 are a defined above, and R4 represents a hydrogen, a linear or branched alkl group having 1-6 carbon atoms or the like.) [Chemical formula 3] (1) (In the formula, n represents an integer of 0-3, and R1 represents a hydrogen, a linear or branched alkyl group having 1-6 carbon atoms or the like.)